Safety key for locks



Aug. 18, 1931. E. SCHMID SAFETY KEY FOR LOCKS Filed June 15, 1929Patented Aug. 18, 1931 UNHTED STATES ERNEST SGHMID, OF GLADSTONE, OREGONV SAFETY KEY non LOCKS 1 Application filed. June 15,

This invention relates to keys and more particularly to keys to be leftin the keyhole after the usual key has thrown the bolt, to protect thelock against an unauthorized per- '5 son unlocking or withdrawing thebolt to unlocked position.

The object of the present invention is to provide a safeguard for lookswhich may be operated from only one side and which will insure the doorremaining locked to all but the proper person.

A further object is the provision of means which may be left in thekeyhole to prevent the insertion of a key which would ordinarily operatethe look.

A still further object is the provision of means which willautomatically take a position to prevent a duplicate key from beingused.

A still further object is to provide a key capable of beingautomatically retained in a keyhole and requires but the ordinarymotions used in ordinarily opening or locking a lock to actuate same.

The invention is illustrated in the accom panying drawings in whichFigure 1 is a front view of the key showing the sections securedtogether to insert in a lock.

Figure 2 is a section on line 2-2 on Fig. 1.

Figure 3 is a broken elevation, partly in section, of the improved key.

The key is illustrated in the drawings as of conventional shape having ahandle section 4 and a bit section 5. The two sections when fittedtogether form an ordinary locking key which is no more inconvenient tocarry or use than such a key. The bit section 5 is hollow Z6 andincludes a somewhat elongated portion 12 of uniform diameter throughoutand a somewhat enlarged portion 5 of less length than and of a diametersomewhat greater than that of the portion 12.

The bolt 13 is fitted within the hollow bit 5, this bolt having anenlarged portion 13 fitted within the portion 5 of the hollow bit, suchportion 13 of the bolt being formed with a longitudinally ranging bore 6inter- 50 nally threaded at 7 to cooperate with a stud 8,

1929. Serial m. 371,250.

threaded at 9, projecting from the handle section 4.

The bit section 5 has a bit 10 having a centrally located groovelll cuttherein. From the bolt 13 extends a locking pin 14, the latter beingsemicircularin cross section and is adapted to fit in the groove 11, theflat surface of the pin coming flush with the surface of the bit so asnot to interfere with the insertion and removal of the key in thekeyhole A spring 15 secured to the shank 12 of the bit section at 16 andto the bolt 13 at 17 tends to force the pin away from the groove 11, toextend at an angle with the bit. This provides a means for locking thekey in the keyhole so that it cannot be pushed from the keyhole by theinsertion of any instrument in said hole.

In operation, the usual key is inserted in the key hole to throw thelock bolt in locked position, then the key is withdrawn and therqwimproved key with the handle section and bit section tightly screwedtogether to bring the pin. 14 in the groove 11, is inserted in the keyhole of the lock, with the lower edges of the bit in engagement with thewalls X X 3 of the lock frame. Then by unscrewing the handle section tofree the bolt 13 so that the spring 15 will turn the pin 14 from thegroove 11, as shown in Fig. 2, and by continuing to unscrew the handlesection, it cang be separated and withdrawn from the bit section, withthe latter remaining locked within the lock frame. In this operation, itis to be understood that the bit 10 engages the walls X X of the keyopening and is thereby prevented from turning when screwing orunscrewing the handle section to engage or disengage it from the bitsection. When the pin 14 is swung away from the bit by the spring 15, itprevents the bit being with- 7 drawn from the lock, and at the same timelocks the bit in the frame and prevents the insertion of another key andthus prevents an unauthorized person tampering with the lock.

-To remove the bit section of the key to unlock the lock, it is onlynecessary to insert the stud 8 of the handle section into the bore. 6 ofthe bit section and screw the two sections together. This causes abind-m0 ing action between the handle section and the bolt 13, and thelatter is thus turned with the handle section, and the pin 14: isreturned to the groove 11,whereupon the key as a whole can be withdrawnfrom the lock and the usual key inserted to unlock the lock. Of course,in screwing the sections together to remove the key, the bit 10 isprevented from turning by engaging the walls of the key opening aspreviously described.

What I claim is A key comprising a handle section and a bit section,said bit section including a hollow shank open at one end and closed atthe opposite end and formed with an ofiset bit, the interior of thehollow shank at the open end being enlarged diametrically to provide anabrupt shoulder interiorly of the hollow shank,a bolt mounted formovement Within the hollow shank and formed with parts of differentdiameters to accurately fit the similar parts of the hollow shank, thebolt having a shouldered portion to bear on the shouldered portionwithin the shank, a pin carried by and projecting at right angles fromthe bolt and extended through a slot in the hollow shank, the bitcarried by the hollow shank being formed with a groove to house the pinin one position vof the bolt relative to the hollow shank, one end ofthe bolt being formed with a threaded socket, the opposite end of thebolt being of reduced diameter, and a spring encircling the portion ofreduced diameter of the bolt and terminally secured to the bolt and tothe closed end of the hollow shank, the handle section having a threadedprojection to cooperate with the threaded socket in the bolt.

ERNEST SCHMID.

